Grommet



Patented Aug. 8, 1944 f j 'UNITED STATES PATENT OFFICE 'GRoMMET l Lewis G. Webster and Fred J. Rees, Dayton, Ohio Ap'pucatinn August 1s, 1942, serial No. 455,233

Y (c1. 16-2) A(cimmed lunder the act of March 31883, as v 3 claims.

amended April 30, 1 928; 370 O. G. 757) .The invention'described herein may be manufacturedandused by `or for Government for governmental purposes, without 'the payment to us'of any royalty thereon. i "This invention relates Vto van improved construction of grommet or" sleeve for insertion in an openingin a'Wall, bulkhead, orthe like, for the protection of Wires, cables,-'tubes,'etc., from wear due to. frictional contact with the relatively thin edge, of the opening; Y i

`A principal object of the invention is to provide a device ofv the oharacterjdescribed which may be formed out'of comparatively stiff, though somewhat resilient,v shape-*retaining material such` as a plastic or aA spring metal, thereby releasing strategic materials such as rubber, or the like, fromhwhich conventional design grommets are made,`fo1- othernecessary uses.

Another object ofthe i vention is to provide a device of the character referred to which is constructed so that its; insertion in a hole for its intended, use isfmadeeasier'without requiring any specialto'ols for suchemplacement.

` Another object ofthe 'invention is to provide a device of the kcharacter referred to whose construction isisucwh astoenable it to be self-locking' in position `inaholein Which it may be inserted forfitsintendedpurpose sothat the device is thereby maintained more securely' in its desired position. j

The embodiment of the invention shown comprises a grommet inthe formof a sleeve having a spiral lperipheral groove adapted to receive therein between the sides thereof material surrounding an opening in a wall or the like whereby to maintainithe sleeve in position in such opening againstfaxial displacement therefrom when such material is so received in said groove. Pref-v erably, as in the: constructionv illustrated, the grommet issplit or `severed radially on one side of its-central 4'axis,' its` ends at the point of 'cleavage being oiifset `axially so 'as to provide a sleeve-like member of spiral form having a peripheral groove, followingthe spiral convolution o1 saidmember, thegroove being designed to receive'therein thematerial of the wall around the hole-into which the: grommet is to be inserted. The adjacent extremities ofthe spiral provided by the severance of the" sleeve Vare preferably provided vvith-planar meeting faces, the plane of which is inclined at an angle to the axis of the sleeve lmember or 'grommet and the same ispreferably radially contracted initially so that, upon application of pressure to the-adjacent ends of the grommetin opposite directions axially there- ISB`vi of, to bring the peripheral groove into circumferential continuity, the sleeve will be diametrically expandediby engagement of the'inclined 'planar meeting faces of the spiral extremities of the sleeve. The material of which the grommet is composed, though comparatively stiff and shape retaining, is of sufficient resiliency to permit the diametrical expansion above mentionedi The construction is such that-the grommetmay be screwed into position lining an opening in a Wall or the like by causing the material around such opening to engage in Aone portion of the peripheral groove and Athen rotating the sleeve, said sleeve being yieldable to permit the ends ci the groove to be brought into circumferential alignment uponA such `rotation.-

Other objects, vadvantages, and.v `feat-muresfof' novelty will be apparent as the description of the invention proceeds in conjunction Withvthe draw-r' ingin'which: 'i y Figure 1 is a perspective view of a deviceconstructed in accordance with the invention.' l n Figure 2 isa View showing they device inserted in a hole lin a'w'all invposition for" its Vintended use, the devicev l being 1Vviewed inv edge elevation and the wallfbeing shown in section. j

Figure "3' glprs'petivevi w or; thdevicep: the invention, illustratingthe method of inser-y tion of the saine` foritis'intendeduseiri ajliole in awaii. p l fi it; i j NOW, describing'the Vinvention-'in detail, the 'grommet comprises'a' sleeve-like member, generally designated bythe letter A4-which is ,radially split 'at one side -f ftheflongitudinal Yaxis Vi,;hereoi; as indicated at 59 in Figurel L 2"t'o k provide adjacent en ds l and'Z, Whicliiii theffofrmationofthesleeve Aare offset axially'so;thattlijsleeve ha'sa" sub-V4 stantially spiral configuration, 'the 'body' of thef sleeve comprising one-fullo nvolutionjof aspiral.y The radial Vse` `verandeA of the sleeinejA at one side of the longitudinal-axisthereof provides `-the spinalA or convolute extremities I and 2 vvviththe planar' meeting faces 4lafandfila, tlfiegplane of whichj'isv inclined at an angle-'to 'the' 'longitudinalaxisfof the member A. 4This member A {is providedjwit'hf aperipheral i groove 3lv`vhich- Vvfollows fthe, convolfu tion o'f-the s'piral-andsaid groove is designed'jto receivel therein the 4material 'off a Vwall 4 adjacentv the hole 5 within -Whichthe vgrominet comprising the sleeve member A- ydes'ignedto-"oe inserted fori' l 1111-11; g .5 i1.. 1; e L.. 'y

k' The "sleeveC member n 1 yA is preferablycomposedofA a relativelystiff sh pe-retaining material Ewl'iic'hl neverthelesshas sicien-tres'iliency-tofperinitithe sleeve member A to be slightly "diametric'ally ex' clined meeting faces Ia and 2a during such relative axial movement of the spiral extremities.

of the sleeve.

Many of the plastics, such as those made from cellulose acetate, provide suitablematerials out of which the grommet comprising the Ysleeve A may be made, or spring steel or other spring metal may compose the body of the sleeve. One

face of the sleeve A may be provided withslots 'I and 8 for engagement by a suitable bit or other tool for a purpose hereinafter mentioned. Both faces of the sleeve A may be provided with such slots if desired.

Figure 1 illustrates the grommet comprising.

the sleeve A ini its normal condition prior to emplacement in the hole 5 of the wall 4. It is to be particularly noted that the spiral extremities`or ends I and 2 of the spiral convolution, into which the sleeve A is castare axially offset relative to one another, andthe whole body of the sleeve is somewhat radiallycontracted in its normal condition prior to emplacement in the hole 5, of the wall 4 forV its intended use, so that the whole body of the sleeve Arinitially assumes a spiral configuration with the peripheral groove 3 extending around the bodyAof the sleeve A in a spiral path like a screw thread. While the spiral extremities I and 2. are axially oiset Yrespecting one another in theinitial condition of the sleeve A, nevertheless, the planar meeting facesla and 2a, provided at these extremities are in ilat engagement for a portionof theirrespective sur-` faces. .1

In theuse of thegrommet of the invention, the device is insertedin the hole 5 of the wall 4 by starting one extremityof the groove 3, such as that. defined at the face 2a, into the hole 5 in the manner indicated in yFigure 3 and then rotating thesleeve.` A about its longitudinal axis in the direction of the arrow indicated in Figure 3 so asto screw the grommet. into the hole 5, the material ofthe wall 4 entering the peripheral groove 3 Pwhich acts in the manner .of av screw thread.V

A suitable bit or other tool may be inserted in the slots. 1 and B for facilitating this rotation of the sleeve A. After thepgrommet is started into the hole 5, as aboveindicated, .rotation may be continued until the material. of the wall V4 surroundingthe hole 5 has entered the entire length ofthe groovel3, at which time said vgroove will be in vcircumferentialcontinuity as indicated in Figf ure2.

During the rotation of the sleeve A to screw the same into positionfin the hole 5, it will be apparent that the material of the wall 4 surrounding the hole will act inthe groove.. 3 to apply axial pressure iny oppositiedirectionsA to thespiral extremities land 2, causing the same to move relatively to. one another by engagement ofthe inclined planar meeting faces la and 2a so as to cause the sleeve A to be diametrically expanded until. the sleeve A is fullyfpositioned in the hole 5 at which timethe extremities of thev groove 3 will be in' circumferential alignment or continuity.

CII

Once the grommet is started into the hole 5, by engagement of the material of the'wall 4 surrounding said hole in the groove 3 by partial rotation of the sleeve A in the manner indicated in Figure 3, it is not necessary that rotation of the sleeve A be continued until said sleeve ls fully positioned in Vthe hole 5, as indicated in Figure 2, in order to` get the sleeve into that position. At a certain point'after'the starting rotation has been accomplished and a part of the material of the wall 4 surrounding the hole 5 has entered the groove 3, the application of external axial pressure to the area indicated by the numeral I0 on the face 6 near the spiral extremity I will cause the sleeve A to be sprung into fully seated condition with the material of the wall entering the entire extent of the groove 3 as indicated in Figure 2. This action is due to the inherent resiliency of the sleeve member A, theA fact that the same is initially slighly radially contracted, and to the action of the inclined planar meeting faces la and 2a at the spiral extremities of the sleeve A in diametrically expanding the sleeve A when axial pressure is applied in opposite directionsy to the spiral extremities I and 2 of said sleeve.

It will be apparent that, when the grommet is fully positioned in the hole 5, with the material of the wall 4 surrounding said hole fully entering the groove 3 throughout the extent thereof, the inherent spring action or'resiliency of the sleeve A will cause the grommet to be tightly maintained in position due to the natural tendency of the spiral extremities I and 2 to tend to resume or spring back to their initial axially offset condition respecting one another as indicated in Figure 1.

Modifications of the structure within the scope of the invention will readily suggest themselves to those skilled in the art and we therefore do not desire tobe limited to the specific structure of thepreferred. embodiment of the invention shown and described. For example, it is contemplated that,.within the scope of the invention, the grommet need not necessarily be resilientor be radially split and, in ysuch event, the spiral peripheral groove will, nevertheless, enable the grommet to be screwed into the opening and securely maintained in such position bythe binding action of said spiral groovewith respect to the material surrounding the opening entering said groove. However, the preferred, resilient split-sleeve Vembodirnentof the invention, particularly described herein, is considered to have very material advantages not otherwise obtained, as will be apparent from the foregoing.

Having thus described our invention, what we claim as new and desire to secureby Letters Patent ofthe United States is:

l. A grommet ofthe class described comprisin'g a sleeve-like member of spiral form having a peripheral groove following the spiral convolution of said member, the, latter having its spiral extremities normally arranged in an axially off-l set abutting relation, said extremities of said member having planar meeting faces, the plane of which is inclined at an angle to the axis of the sleeve, whereby upon application of pressure to said extremities of .said sleeve in opposite directionsaxially thereof to bringthe peripheral groove into circumferentialcontinuity, said sleeve will be diametrically expanded by engagement ,orl the inclined planar meeting faces of thek spiral extremities of the sleeve. p

2,. A .grommet of the ,class described comprising a sleeve-like member of spiral form having a peripheral groove and having its spiral extremities arranged in an axially offset adjacent relation, said member being composed of comparatively stii shape-retaining material having sufcient resiliency to permit said member to be radially expanded, the spiral extremities of said member having planar meeting faces the plane of which is inclined at an angle to the axis of said sleeve whereby, upon application of pressure to said extremities of said sleeve in opposite directions axially thereof to bring the peripheral vgroove into circumferential continuity, the sleeve will be diametrically expanded by engagement of the inclined planar meeting faces of said extremities of the sleeve, said sleeve being normally slightly radially contracted in its initial condition prior to the application of such axial pressure.

3. A grommet of the class described comprising a sleeve radially severed at one side of the longitudinal axis thereof and composed of comparatively stiff shape-retaining material having "suflicient resiliency to permit such sleeve to be radially expanded, said sleeve having a peripheral vgroove, the portions of the sleeve adjacent the "point of severance being axially movable rela- ,tive to one vanother to enable the ends of the groove at the point of severance to be moved into yand out of circumferential alignment, the extremities of said sleeve portions adjacent the point of severance having inclined planar meeting faces, the plane of said faces ybeing inclined at an angle to the axis of said sleeve, whereby upon relative axial movement of said sleeve portions toward one another, said sleeve Willbe diametrically expanded by engagement of said meeting faces, said sleeve being normally slightly radially contracted with said sleeve portions normally arranged in axially offset abutting relation in its initial condition prior to axial movement of said sleeve portions as aforesaid.

LEWIS G. WEBSTER. FRED J. REES. 

